WOW. Yes, it seems the family was / is big. The Yamashiro family grave is in walking distance from the Himeyuri shrine. I have photos from when we were there of the grave site, its amazing.
From what you wrote, we could be related. I don't have many relatives here, Hawaii, but there is supposed to be a larger group of relatives in Brazil.
not sure how safe this site is so if you want, please send me your email to
d.shiro@ymail.com. Not my mail email but one I do use. Sorry, sometimes internet can be scary